Is rudder trim OK?

[atv223]

Originally Posted by TheBum

I fixed it for ya.

Thanks!

[atv223]

Originally Posted by John Shipley

You guys are talking about two different things. The original question was "is using trim ok"......not about using sub trim. Sub trim can be used to center your servo so it is centered in its travel range.......not a huge deal on a 130, but good practice. Sliding the servo or adjusting the rudder push rod keeps every thing centered. This is what works for me and I do not have to use any trim to adjust drift.

I am still quite new to all this, but I was talking about trim, not sub trim, because like you age suggesting, I was under the impression that sub trim was for dealing with centering servos when center fell between 2 mechanical adjustment points and trim adjusting for drift when everything is set up as it should be.

I guess what I don't understand is with the trims set neutral, why isn't the FBL unit sensing the drift and correcting for it? Isn't that what it does, hold the head in place when hovering?

[John Shipley]

Like everyone else, I am still learnig the facts vs fiction on the 130. But the basics of gyro's, flybarless systems and drift is this, Drift can be caused by a few things.The 2 major ones are not being set up mechanically correct and the other is that the heli was moved prior to all system initializing. I covered the mechanic's, so let look at the intialization process. When you first plug in your heli, the RX and gyro's are powering up and "seeing" their centers. On a micro beast like is in the 300X or the V-bar, you wait until you see the blades move up and down and then it is safe to move the heli. If you move the heli prior to this, the gyro and RX may see a differnt center, because they do not intialize exactly at the same time. So if your gyro poweres up first and see's one center and then the heli is moved, the rx may see another center and then the gyro will try to correct and it will drift. In the worst case I have seen large helis moved to the flight line after plugging in, but before they initialize and on take off the gyro tries to find its center and the heli flips over or worse. So the very first thing to do when checking for drift, bedisdes making sure your mecanics are right, is to not move the heli in the first few moment after you plug in the battery......not even a slight amount. Vibration, servo not centering and a few others can also cause problems. If you use trim, this is a different center than the gyro was initialized in. So rebinding will help this, but you really want to have everything centered.
I read about guys who have thier heli's setup wrong, but say they fly just fine. This may be, for the type of flight they are doing at the time. But at some point when you start trying the more advanced moves, you may have problems. So it is best to have the heli set up right. Ovverall pitch is a good example....but there are many. If you do not have enough negitive pitch, it is no problem when flying upright, but is a disaster when you fly inverted. Too much pitch is not problem until you jam the sticks in the corners and then the pitch causes too much torque and the gyro can not handle it or the motor bogs and you crash.....and you don't know why. My advice is to get the heli set up right and then fly it that way, instead of setting it up wrong flying it until you get more advanced and then having to do a whole new setup when you get better......J